title: Isolation and biochemical characterization of tyrosinase-rich GERL and coated vesicle in melanin synthesizing cells.
abstract: The site of condensation and activation of tyrosinase prior to melanosome melanogenesis has been investigated using subcellular fractionation and enzymic analysis of so-called Golgi apparatus of melanoma cells. Two different functional units have been found in the so-called Golgi fraction, the tyrosinase-rich GERL-coated vesicle unit and the TPPase-rich Golgi unit. The tyrosinase-rich unit consists of a tubular structure with a cisternal portion corresponding to the three-dimensional structural characteristics of GERL, and spheroid vesicles, corresponding to the currently accepted criteria for coated vesicles. This fact suggests, in agreement with electron microscopic observations, that the GERL-coated vesicle unit is a specialized portion of smooth endoplasmic reticulum having the function of activating and condensing the tyrosinase synthesized by ribosomes.
mesh_terms: D000818:Animals; D004156:Catechol Oxidase / Q000378:metabolism*; D002458:Cell Fractionation; D006224:Cricetinae; D004721:Endoplasmic Reticulum / Q000201:enzymology* / Q000648:ultrastructure; D006056:Golgi Apparatus / Q000201:enzymology* / Q000648:ultrastructure; D008544:Melanocytes / Q000201:enzymology*; D008545:Melanoma / Q000201:enzymology / Q000648:ultrastructure; D008854:Microscopy, Electron; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D009374:Neoplasms, Experimental / Q000201:enzymology / Q000648:ultrastructure; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D004156:Catechol Oxidase; D014442:Monophenol Monooxygenase